Dear Soup,
Memories are not linear to dates' rather they are brought to our current self by 2 ways. Order of importance good/bad and how those emotions attatched, effect us today.
When these negative memories come to mind you have to tell yourself, my father was a flawed man, and I wish he could of been a better father.
Also remind yourself that you are still grieving and allow yourself more time to heal.
May you feel better today!